LIGHT
Early Concepts of light

  • Ancient Greek philosophers thought that light consisted of many particles.
  • Huygens was the first scientist that believed that light was in fact a wave.
  • The light theory was supposted by the fact that light seemed to move in a straight line instead of spreading out like a wave.
  • Scientist now agree that light has a dual nature, part particle and part wave.
The speed of light
  • Speed of Light = extra distance traveled
    extra time measued
Materials which absorbe light witout re-emmitting it are called opaque. when light goes in the enrgy will be transformed into heat.
Electromagnetic waves
electromagnetic-spectrum.jpg
http://images.google.com/imgres?imgurl=http://mail.jsd.k12.ca.us/bf/bflibrary/images/electromagnetic-spectrum.jpg&imgrefurl=http://mail.jsd.k12.ca.us/bf/bflibrary/projects.html&usg=___KLQBIxkJVrZSmW6C_EaWNdestM=&h=346&w=500&sz=29&hl=en&start=1&tbnid=8K533ZWwFJMHUM:&tbnh=90&tbnw=130&prev=/images%3Fq%3Delectromagnetic%2Bspectrum%26gbv%3D2%26hl%3Den%26safe%3Dactive

As you can tell from the diagram above. The waves get smaller and have a higher frequency.

Shadows
  • A shadow is defined as a thin beam of light often called a ray. any beam of light, no matter how wide can be tought of as made of a bundle of rays.
  • A shadow is formed where light rays canot reach.
  • Sharp shadows are produced by a small light source
  • A foggy shadow is produced by a large light source
  • A total shoawos is called an umbra and a partial shadow is a penumbra

coolshadows.jpg
http://www.reallyfunnypictures.co.uk/coolpictures/pics/16.11.08/coolshadows.jpg


Polarization
Used in sunglasses to block out rays of sun
Light will pas through a pair of sunglasses when their polarazation axes are aligned, but not when they are crossed at right angles.
polarizationfigure1.jpg
http://images.google.com/imgres?imgurl=http://www.robotroom.com/Polarizers/VerticallyOrientedPolarizingFilter.gif&imgrefurl=http://www.robotroom.com/Polarizers.html&usg=__mtUaRf5Okr25yNItJhOtwkw6nMc=&h=261&w=437&sz=13&hl=en&start=2&tbnid=F8VNM0VFx6PZEM:&tbnh=75&tbnw=126&prev=/images%3Fq%3Dlight%2Bbeing%2Bpolarized%26gbv%3D2%26ndsp%3D18%26hl%3Den%26safe%3Dactive%26sa%3DN

Light can also be polarized by reflecting off of a surface, if light bounces off of a horizontal surface at a low angle it will bevome horizontally polirized.
Polirized light is used to produce 3D images. Two projectors are used at one time, one projector has a horizontal filter and the other has a vertical lens filter.

3d-free-desktop-wallpapers.jpg
http://images.google.com/imgres?imgurl=http://fantasyartdesign.com/x-images/3d-free-desktop-wallpapers.jpg&imgrefurl=http://fantasyartdesign.com/&usg=__d5JuquUZsHrSav_6rW-jHSnAYr0=&h=768&w=1023&sz=221&hl=en&start=18&tbnid=uk90-BD0o798_M:&tbnh=113&tbnw=150&prev=/images%3Fq%3D3d%2Bimages%26gbv%3D2%26ndsp%3D18%26hl%3Den%26safe%3Dactive